Rust inhibited stabilized hydrocarbon fuel oil



United States Patent RUST INHIBITED STABILIZED HYDROCARBON FUEL OIL Fred B. Fischl, Rahway, John V. Clarke, Jr., Cranford,

and John 0. Smith, Jr., North Plainfieltl, NJ., assignors to Esso Research and Engineering Company, a corporation of Delaware No Drawing. Application September 10, 1956 Serial No. 608,713

9 Claims. (Cl. 44-63) This invention is directed to a novel hydrocarbon fuel oil composition containing a synergistic mixture of additives that effectively inhibit the composition against corrosion of the storage facilities by, and the formation of sludge in, the fuel oil during storage. The additive mixture contains an alkaline earth metal salt of an alkyl phenol sulfide and a complex prepared from an alkyl benzene sulfonic acid, an alkali metal nitrite, and a strongly basic heterocyclic nitrogen compound.

The hydrocarbon fuel oils with which this invention is concerned broadly comprise petroleum hydrocarbon mixtures that are commonly employed in various burner systems, as diesel fuels, or as domestic or industrial heating oils. These fuel oils may be generally characterized as those that consist of a major proportion of hydrocarbons boiling in the heating oil range, i.e. from about 300 F. to about 750 F.

Heating 'oils, particularly those in which the hydrocarbon mixture includes at least 10% of cracked stocks, that is, stocks derived from thermal or catalytic cracking operations, tend to be unstable on storage, forming sediment or sludge, and also tend to corrode ferrous metals with which they come into contact, particularly in the presence of water or water vapor. Such corrosion is obviously undesirable, as is the formation of sediment since the latter may lead to the clogging or fouling of filters, orifices, and fuel lines associated with the burner systems in which the fuel oils are used.

In accordance with the present invention the instability of fuel oils, particularly those containing cracked stocks, can be overcome and the corrosiveness of such fuel oils toward containers in which they are stored can be reduced or eliminated by incorporating therein minor proportions, of the order of no more than about 0.2 percent, and preferably of the order of 0.005 to about 0.1 percent, of a mixture of an alkaline earth metal salt of an alkyl phenol sulfide and a complex prepared by the reaction of an alkyl benzene sulfonic acid, a strongly basic heterocyclic nitrogen compound, and an alkali metal nitrite.

With reference to the alkaline earth metal salts of alkyl phenol sulfides that are to be employed in this invention, these are the types described in the Mikeska patent, US. 2,362,289, the Winning Patent, U. 3. 2,362,291, and the Winning, Van Voorhies and McNab patent, US. 2,294,- 145. These materials have been utilized as addition agents for lubricating oils and are commercially available for that purpose, usually as concentratesin a heavy oil vehicle. For the purposes of the present invention the alkyl phenol sulfides that are to be utilized are preferably those having from to 18 carbon atoms in the alkyl group, as for example the calcium or barium salts of tertiary amyl phenol sulfide, of tertiary octyl phenol sulfide or of dodecyl phenol sulfide. Particularly advantageous are the mixed calcium and barium salts of the type described in the McNab, McNulty and Cross patent, US. 2,480,664.

With reference to the complex which constitutes the 2,888,338 Patented May 26, 1959 other member of the synergistic mixture, this is prepared by heating together an alkyl benzene sulfonic acid, an alkali metal nitrite, preferably sodium nitrite, and a highly basic heterocyclic nitrogen compound. It is preferred that the alkyl benzene sulfonic acid be one with a molecular weight in the range of from about 340 to about 560, i.e. one that will have from about 15 to 30 carbon atoms in the alkyl group, although those having alkyl groups with as few as 5 carbon atoms may be employed.

The heterocyclic nitrogen compound is preferably selected from the group consisting of morpholine and bydroquinolines. Among the hydroquinolines that may be employed are tetrahydroquinoline, 6-ethoxy, 1,2 dihydro, 2,2,4-trimethyl quinoline, and decahydroquinoline.

Other highly basic heterocyclic nitrogen compounds that may be employed include pyrroline or substituted pyrrolines, pyrrolidines or substituted pyrrolidines and piperidine or substituted piperidines. It will be noted that the latter compounds as well as the hydroquinolines and morpholine, are all characterized as being heterocyclic nitrogen compounds in which the heterocyclic rings are essentially cycloaliphatic in nature as contrasted with the aromatic nature of the ring in such heterocyclic nitrogen compounds as pyridine, for example.

In general the complex is prepared by employing the materials in the proportion of 5 to 10 parts of sulfonic acid, 1 to 3 parts of the cyclic nitrogen compound, and 1 to 6 parts of sodium nitrite, the parts being by weight.

The complex and the alkaline earth metal salt may be used in the proportions of from 3 parts by weight of the complex to 1 part of alkaline earth metal salt to about 1 part of the complex to 3 of the metal salt. The preferred range is from equal proportions to about twice as much of the complex as the metal salt.

The following examples serve to illustrate this invention.

EXAMPLE 1 A solution of 20 grams of sodium nitrite in 30 grams of water was mixed with 6.4 grams (0.048 mole) of tetrahydroquinoline and 50 grams of a 45% solution of mixed alkyl benzene sulfonic acids of about 440 average molecular weight in mineral oil. The mixture was heated for 2 hours at 300 F. until all of the Water had been removed. The mixture was then filtered to remove excess sodium nitrite. The complex was composed of the following:

Percent Sulfonic acid 37.0 Tetrahydroquinoline 10.2 Sodium nitrite 7.8 Mineral oil 45.0

EXAMPLE 2 Percent Sulfonic acid 34.7 6 ethoxy, 1,2 dihydro, 2,2,4 trimethyl quinoline 16.1 Sodium nitrite 6.7 Mineral oil 42.5

EXAMPLE 3 A complex was similarly prepared by mixing a solution of 20 grams of sodium nitrite in 30 grams of water with 4.2 grams (0.048 mole) of morpholine and 5.0 grams of the oil solution of the sulfonic acids used in Example 1, followed by heating the mixture for 2 hours at 300 F. and filtering.

EXAMPLE 4 A commercial heating oil was selected for stability tests using the oil itself as well as mixtures of the oil with various additives as will be explained below. The oil was a blend of 50% virgin heating oil and 50% cracked To various samples of the fuel oil were added the materials set forth in Table 1 below. The base fuel and each of the additive blends were subjected to a stability test which consisted in storing the fuel oil in a glass container for a period of 16 hours while maintaining the temperature at 210 F. At the end of the 16 hours the fuel oil was filtered and the amount of sediment that had been formed during the storage period was quantitatively determined. The color stability of the various fuel oil samples was also determined by measuring the amount of White light that could be transmitted through each of the filtered samples after the storage test relative to the amount of the same white light that could be transmitted through the unheated, uninhibited base fuel.

Other portions of each of the blends, as well as the uninhibited base fuel, were also subjected to a rusting test in which steel strips were immersed in a mixture of water and fuel for a period of 15 days at room temperature. The appearance of the steel strips at the end of this period was noted. Table 1 sets forth the data obtained in each of these tests.

Table 1 INHIBITION OF CRACKED HEATING OIL AGAINST SEDI- MENT FORMATION, COLOR DEGRADATION AND RUST- IN G Insoluble Sediment Formed Percent Static Rust Additive After 16 olor Test Hours Hold Appearance 210 F., of Steel Strip mg./600 g. Oil

None 41. 7 68 Heavy Rust. 0.02% Ca-Ba Alkyl Phenol Sul- 33.0 77 Do.

fide Concentrate 0.05% Tetrahydroquinoline 30 58 Do. 0.025% 'Ietrahydroquinoline plus 1. 75 Do.

0.025% Ca-Ba Alkyl Phenol Sulfide Concentrate. 0.05% Example 1 Concentrate 39.8 35 No Rust. 0.05% Example 2 Concentrate- 37. 4 42 Do. 0.02% Example 1 Concentrate plus 0. 8 91 Do.

0.02% Ca-Ba Alkyl Phenol Sulfide Concentrate. 0.02% Example 2 Concentrate plus 0. 8 91 D0.

0.02% Ca-Ba Alkyl Phenol Sulfide Concentrate.

Percent transmission of white light through filtrate from 16 hr. 2l0 F. sediment test, relative to unheated, uninhibited base fuel.

A commercially available 37 percent solution, In mineral 011, of a. mixed calcium-barium salt of tertiary octyl phenol sulfide (calcium content 2%; barium content 2.4%).

It will be noted from the data in Table 1 that neither the mixed Ca-Ba alkyl phenol sulfide alone nor the complexes of Examples 1 and 2 alone were particularly effective in reducing the formation of insoluble sediment. The mixture of tetrahydroquinoline and the mixed Ca-Ba phenol sulfide did effectively reduce sediment formation but did not prevent rusting. On the other hand, the mixture of mixed Ca-Ba alkyl phenol sulfide with either of the complexes of Examples 1 and 2 very effectively reduced sediment formation, to a value one-half that of the mixture of tetrahydroquinoline and the Ca-Ba alkyl phenol sulfide. Furthermore, the mixtures of the present invention were effective in preventing rusting. Additionally these mixtures were more efiective than any of the other additives tried as regards preventing degradattion of the oil as indicated by the color hold test, holding the color to 91% of its original value.

As the mixed Ca-Ba alkyl phenol sulfide was employed as a 37% concentrate, the actual concentration of this material in the fuel oil was 0.0075%. Likewise, since the complexes of Examples 1 and 2 contained approximately 35% oil, or in other words since the complexes constituted approximately 65% concentrates in oil, the actual concentration of the complexes in the fuel oil compositions was about 0.013%. Thus the total con centration of active material was about 0.02%, and the proportion of the alkyl phenol sulfide salt to the complex was approximately 1 to 2.

EXAMPLE 5 For the purpose of further evaluating the present invention, the following additional tests were made. For these tests, reaction products were prepared employing the procedure of Examples 1 and 2, with the exception that the sodium nitrite was omitted in each instance.

Thus a material identified as Reaction Product A was prepared by the procedure of Example 1, except that 30 grams of water was substituted for the aqueous solution of sodium nitrite. Similarly, a material identified as Reaction Product B was prepared by the procedure of Example 2, substituting 30 grams of water for the aqueous solution of sodium nitrite. In each instance the mixtures were heated for 2 hours at 300 F. and then filtered.

Blends were prepared by dissolving 0.2 gram of Reaction Product A and 0.2 gram of calcium-barium alkyl phenol sulfide concentrate in one 1000 gram sample of heating oil and 0.2 gram of Reaction Product B and 0.2 gram of calcium-barium alkyl phenol sulfide concentrate in a second 1000-gram sample of heating oil. To each of these blends one gram of solid sodium nitrite was added and the mixtures were stirred for one hour at F. and then filtered to remove excess sodium nitrite.

Additional blends were prepared by dissolving 0.2 gram of the complex of Example 2 and 0.2 gram of the complex of Example 3 in separate 1000 gram samples of heating oil, 0.2 gram of calcium-barium alkyl phenol sulfide concentrate being also added to each of the latter blends. As in Example 4, the heating oil employed in preparing each of these blends was a mixture of 50% virgin heating oil and 50% cracked stocks, and the cal cium-barium alkyl phenol sulfide concentrate was a commercially available 37% solution in mineral oil of a mixed calcium-barium salt of tertiary octyl phenol sulfide.

The four heating oil blends prepared as described above were subjected to a static rust test in the following manner.

In each instance 300 cc. of the heating oil blend was mixed with 30 cc. of distilled water and placed in a container. A polished steel strip was immersed in each of the mixtures of water and fuel oil, and the containers were stored in the dark for a period of 39 days at room temperature. At the end of the test period, the heating oil samples and the steel strips were examined. The results obtained are presented in Table 2.

Table 2 RESULTS OF 39 DAY STATIC RUST TEST Rust Material Added to Heating Oil on Appearance of Sample After Strip Test 002% Example 2 Concentrate None Oil layer dark amber. No plus 0.02% Ca-Ba Alkyl deposits in oil, on strip or Phenol Sulfide Concentrate. on container walls.

0.02% Reaction Product A plus do- Oillayer green-black. Black 0.02% Ca-Ba Alkyl Phenol greasy deposit on test strip Sulfide Concentrate plus and container walls. Black N aNO added separately. deposits in oil layer.

0.02% Reaction Product B plus .do Oillayer green-black. Black 0.02% Ca-Ba Alkyl Phenol greasy deposit on test strip Sulfide Concentrate plus and container walls. Blaclr N aNO added separately. deposits in oil.

0.02% Example 3 Concentrate do-- Oil layer dark amber. N plus 0.02% Ca-Ba Alkyl deposit on strip, container Phenol Sulfide Concentrate. walls or in oil.

The results of the tests as set forth in Table 2 establish that although the separate addition of sodium mtrite does effectively prevent rusting, it is necessary to prepare the complex of the present invention rather than to add sodium nitrite separately in order to prevent deterioration of the oil. In each case 'Where the sodium nitrite was added separately, sediment formation occurred during the test, whereas when the complex of the present invention was employed the oil retained its amber color and no sedimentation or deposit formation occurred.

Although the present invention is primarily directed toward fuel oils consisting of distillate hydrocarbon fractions it is also applicable to fuel oils containing small proportions, of the order of 10 percent or more, of residual hydrocarbons. It is also to be noted that the specific examples herein described have been presented only for the sake of illustration and that the invention is not to be limited thereto.

All modifications coming within the scope of the appended claims are contemplated in the practice of this invention.

What is claimed is:

1. A fuel oil composition consisting of a major pro"- portion of hydrocarbons boiling in the fuel oil boiling range and a minor proportion of a mixture of an alkaline earth metal salt of an alkyl phenol sulfide, in which the alkyl group has from 5 to 18 carbon atoms and the alkaline earth metal is selected from the group consisting of calcium and barium, with a complex prepared by the reaction of: from 5 to parts of an alkylated benzene sulfonic acid having from 5 to 30 carbon atoms in the alkyl group; from 1 to 6 parts of an alkali metal nitrite; and from 1 to 3 parts of a highly basic heterocyclic nitrogen compound selected from the group consisting of morpholine and hydroquinoiines; said reaction producing said complex being conducted at a temperature and for a period of time sufiicient to remove all of the water from said complex; the ratio of alkaline earth metal salt to complex being in the range of from 3 to 1 to 1 to 3, said mixture being present in an amount not more than about 0.2 percent but sufiicient to inhibit the formation of sediment in said fuel oil.

2. Composition as defined by claim 1 wherein said alkylated benzene sulfonic acid has from 15 to 30 carbon atoms in the alkyl group.

3. Composition as defined by claim 1 wherein said alkaline earth metal salt comprises a mixed calciumbarium salt of tertiary octyl phenol sulfide.

4. Fuel oil composition as defined by claim 1 wherein the hydrocarbons include at least 10 percent of cracked stocks.

5. Composition as defined by claim 1 wherein said heterocyclic nitrogen compound comprises tctrahydroquinoline.

6. Composition as defined by claim 1 wherein said hctcrocyclic nitrogen compound comprises 6-cthoxy, 1,2- dihydro, 2,2,4-trimethyl quinoline.

7. Composition as defined by claim 1 wherein said heterocyclic nitrogen compound comprises morpholine.

8. Composition as defined by claim 1 wherein said mixture is employed in a concentration range of from 0.005% to about 0.1% by Weight.

9. Composition as defined by claim 1 wherein said mixture comprises from approximately equal quantities of said alkyl phenol sulfide alkaline earth metal salt and of said complex to approximately twice as much of the said complex as said metal salt.

References Cited in the file of this patent UNITED STATES PATENTS 2,297,666 Wachter Sept. 29, 1942 2,409,687 Rogers et a1 Oct. 22, 1946 2,419,327 Wachter et al. Apr. 22, 1947 2,533,300 Watkins Dec. 12, 1950 2,582,733 Zimmer ct al. Jan. 15, 1952 2,598,725 Shcldahl June 3, 1952 2,612,439 McNab Sept. 30, 1952 2,626,207 Wies et al. Jan. 20, 1953 2,639,227 Glendenning et al May 19, 1953 

1. A FUEL OIL COMPOSITION CONSISTING OF A MAJOR PROPORTION OF HYDROCARBONS BOILING IN THE FUEL OIL BOILING RANGE AND A MINOR PROPORTION OF A MIXTURE OF AN ALKALINE EARTH METAL SALT OF AN ALKYL PHENOL SULFIDE, IN WHICH THE ALKYL GROUP HAS FROM 5 TO 18 CARBON ATOMS AND THE ALKALINE EARTH METAL IS SELECTED FROM THE GROUP CONSISTING OF CALCIUM AND BARIUM, WITH A COMPLEX PREPARED BY THE REACTION OF: FROM 5 TO 10 PARTS OF AN ALKYLATED BENZENE SULFONIC ACID HAVING FROM 5 TO 30 CARBON ATOMS IN THE ALKYL GROUP; FROM 1 TO 6 PARTS OF AN ALKALI METAL NITRITE; AND FROM 1 TO 3 PARTS OF A HIGHLY BASIC HETEROCYCLIC NITROGEN COMPOUND SELECTED FROM THE GROUP CONSISTING OF MORPHOLINE AND HYDROQUINOLINES; SAID REACTION PRODUCING SAID COMPLEX BEING CONDUCTED AT A TEMPERATURE AND FOR A PERIOD OF TIME SUFFICIENT TO REMOVE ALL OF THE WATER FROM SAID COMPLEX; THE RATIO OF ALKALINE EARTH METAL SALT TO COMPLEX BEING IN THE RANGE OF FROM 3 TO 1 TO 1 TO 3, SAID MIXTURE BEING PRESENT IN AN AMOUNT NOT MORE THAN ABOUT 0.2 PERCENT BUT SUFFICIENT TO INHIBIT THE FORMATION OF SEDIMENT IN SAID FUEL OIL. 